(1) Field of the Invention
The invention relates to a parking lock system for an automatic transmission of a motor vehicle, wherein the automatic transmission has an actuator which can disengage a locking element in the automatic transmission, with the locking element being held in the locked position by spring force, and a locking assembly is provided which is connected to the locking element by means of an actuating element and which has a knee lever which can fix the actuating element so as to prevent engagement of the locking element in the automatic transmission.
(2) Description of Related Art
Parking lock systems of this type are required in conjunction with automatic transmissions of motor vehicles. They are used to prevent in the event of a system failure a locking element in the automatic transmission from engaging in a transmission pinion, and hence unintended blocking of the transmission—for example in the event of a system failure during travel. However, the function of the locking element is designed so that it engages—in the absence of specific countermeasure—in a transmission pinion with a spring force so as to prevent unintentional movement of the vehicle—even in the event of a system failure—when the parking lock is engaged. If such locking element were to engage automatically with the transmission during travel, i.e., when the automatic shifter is not in the “P” position, then the transmission could be damaged. The driving safety may also be seriously impaired.
A number of parking lock systems with interlock assemblies are known in the art. In particular, the laid-open application DE 10 2005 002 446 A1 should be mentioned, which discloses a parking lock of an automatic transmission for a motor vehicle which can be held in its unlocked position by a locking member, which can be operated with an actuating drive and moved by a spring force into the locked position, with a holding device, which is provided in addition to the actuating drive and acts upon the locking member by way of a locking element configured to hold the locking member in its unlocked position. The holding device has a knee lever with a first knee lever part, a knee lever joint, and a second knee lever part, wherein the knee lever is locked in the unlocked position of the locking member by way of a locking element in a nearly extended position.
Such implementation of a parking lock, which also corresponds to the preamble of the present claim, goes fundamentally in the intended direction, because by using the knee lever the parking lock can be locked or unlocked, respectively, by applying relatively small forces.
Disadvantageously, however, the knee lever in the locking assembly for the parking lock according to the state-of-the-art must be precisely adjusted, because it is almost impossible to incorporate tolerances in the illustrated embodiment, so that this type of embodiment requires a correspondingly high adjustment complexity during installation of the parking lot system, in particular the locking assembly, which must be adapted to the individual installation position.
It is therefore an object of the invention to provide a parking lock system for an automatic transmission of a motor vehicle with a locking assembly, wherein the locking assembly should be designed to enable greater tolerances in the adjustment after installation of the system or to eliminate additional adjustments entirely.